Vacuum Booster Air Flow Control for Engine Parasitic Drag Reduction
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Solution Overview
Problem
Existing motor vehicle braking systems that rely on vacuum pumps for load assistance suffer from parasitic drag and reduced fuel efficiency due to the direct engine driving of vacuum pumps, which results in unnecessary energy consumption when the braking system is not in use.
Innovation Solution
A method and system that control the flow of air to a vacuum servo booster by establishing and terminating a vacuum level in the booster device using a pump, with a directional control valve to manage the pressure differential, allowing air flow direction changes between the pump's pressure chambers and the atmosphere, thereby optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a vacuum pump is driven directly by the engine to generate vacuum for the booster device, then the vacuum level is maintained, but parasitic drag increases and fuel efficiency decreases
Solution Approach 1:
The vacuum pump operates periodically rather than continuously. The control system monitors the vacuum level in the booster device and activates the pump only when the vacuum level drops below a threshold, thereby eliminating continuous parasitic drag while maintaining reliable vacuum levels when needed.
Solution Approach 2:
The system transitions from a static continuous operation mode to a dynamic controlled operation mode. The pump's operation is dynamically adjusted based on real-time vacuum level feedback, allowing the system to optimize between maintaining vacuum and minimizing energy consumption.
2Reliability
If the pump continues to operate to maintain vacuum, then the vacuum level is ensured, but unnecessary energy consumption occurs during non-braking conditions
Solution Approach 1:
The control system implements feedback by continuously monitoring the vacuum level in the booster device and using this information to control pump operation. When the vacuum level is sufficient, the pump is turned off, eliminating unnecessary energy consumption while ensuring vacuum availability when needed.
Solution Approach 2:
The system uses the vacuum level itself as the control signal for pump operation. The vacuum condition in the booster device directly determines whether the pump should be operating, creating a self-regulating system that automatically balances vacuum maintenance with energy conservation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces parasitic drag on the engine and enhances fuel efficiency by terminating the air flow when the predetermined vacuum level is reached, minimizing unnecessary energy consumption during non-braking conditions.
Implementation Method 1
establishing a level of vacuum, i.e., negative pressure, in a booster device by generating the flow of air from the booster device using a pump
Implementation Method 2
The act of terminating the flow of air may be accomplished via a directional control valve such that the termination of the flow of air reduces a pressure differential across the pump
Data Source
AI summary
A method for controlling a flow of air includes establishing a level of vacuum in a booster device by generating the flow of air from the booster device using a pump. The method also includes determining whether the level of vacuum in the booster device has reached a predetermined value. The method additionally includes terminating the flow of air from the booster device when the level of vacuum in the booster device has reached the predetermined value. A system for controlling a flow of air according to the method may be incorporated into a motor vehicle having an internal combustion engine that is adapted to drive the pump.